1. Field of the Invention
The present invention relates generally to portable vehicle lifts. More particularly, the invention concerns wireless portable vehicle lift systems.
2. Description of the Prior Art
The need to lift a vehicle from the ground for service work is well established. For instance, it is often necessary to lift a vehicle for tire rotation or replacement, steering alignment, oil changes, brake inspections, exhaust work, and other automotive maintenance. Traditionally, lifting a vehicle has been accomplished through the use of equipment that is built-into the service facility, such as either lift units with the hydraulic actuator(s) installed below the surface of the floor or two and four post type lift systems installed on the floor surface. These built-in units are located at a fixed location at the service facility and adapted to engage the vehicle frame to lift the vehicle from the ground. However, built-in units tend to be relatively expensive and are sometimes not as useful as they might otherwise be due to their immobility.
In an effort to increase the versatility and mobility of lift devices and reduce the need to invest in permanently mounted lifting equipment, devices commonly known as a mobile column lifts (MCL's) have been developed. Traditional MCL's use a number connecting lines or wires to provide electrical power and/or communication of the MCL's. The lines or wires that are connected between the MCL's allow the vehicle to be raised or lowered in a coordinated synchronous fashion. However, the lines and wires used to connect the MCL's extend across and are looped within the working area. The presence of these wires and lines in the work area poses a hazard to people working near the vehicle, and the connecting lines may be damaged by vehicles driving over them.
An apparatus for lifting a vehicle using multiple MCL's is described in U.S. Pat. No. 6,634,461, the entire disclosure of which is incorporated herein by reference. The lifting devices disclosed in the '461 patent are coordinated by wireless signals, such as radio frequency (RF) signals, and powered by rechargeable batteries in each lift unit. By these means, the lifting devices of the '461 patent eliminate the need for both power cables and control cables.
Although the lifts system disclosed in the '461 patent represented a significant advancement in the field of portable vehicle lifts, efforts to improve lift safety, reliability, efficiency, ease of operation, and cost effectiveness continue.